Baltimore Checkerspot Butterfly Colony

Caumsett State Historic Park Preserve contains the only known breeding colony of the Baltimore Checkerspot butterfly on all of Long Island. While this butterfly is found throughout New York State there have only been 4 recorded sightings on Long Island over a period of 40 years prior to its discovery at Caumsett in 2009.

Adult Baltimore Checkerspot Butterfly in its full glory of colors at Caumsett.

Adult Checkerspot on Canada thistle.

Adult Checkerspots enjoying the nectar of Butterfly weed (Asclepias tuberose) at Caumsett.

Management

The Checkerspot’s habitat needs to be managed for its fragile population to survive. Mowing during an active life cycle stage jeopardizes its survival especially being a single brood species. Fortunately, proper management can be achieved by mowing the butterfly habitat during a specified time period. This mowing window commences when the ground has hardened generally after the first hard frost. As the air temperature decreases the larvae migrate under the dense grass mat where they are protected from the mower blades and weight of tractor tires. Mowing can occur up until March 31 after which time the larvae can emerge. Another important function of mowing is to ensure that the host plant will continue to thrive and not be shaded out by other vegetation.

Life Cycle Timing at Caumsett

In late April the larvae begin to emerge and by early May they become easy to spot on the English plantain. Larvae have been found as late as June 22 overlapping with chrysalises, which can be present to the end of June. Adult flight has occurred between June 5 and 12 but more often during the early days of June. Few adults are present after July 1 and larvae tents are found in the third week of July.

Larvae found in Bull Pen Field on 6 May 2017.

Chrysalis of Baltimore Checkerspot Butterfly.

Worn adult on 30 June.

Active larvae tent wrapped in English plantain leaves in August.